We have one NEC Aspire system and one NEC SV8100 in different offices.
both are connected on Netlinks.
NEC Aspire we can take trunk lines by dialing 2 and on NEC SV8100 we can take trunks by dialing 0. Both Trunk lines are from different vendors.

i want to use NEC Aspire Trunks (2) when NEC SV8100 trunks goes down. i tried to configure everthing but its not working.

Please suggest.